change chart to be cluster instead of tenant; make client and server certs completely optional; also make backups optional

[jessebot]

now client and server certs have their own respective sections that can be enabled and generation is optional for both:

certificates:
  server:
    # -- enable using server certificates
    enabled: false
    # -- generate server certs using cert-manager. if true the following
    # are ignored: certificates.serverTLSSecret, certificates.serverCASecret
    generate: false
    # -- name of existing Kubernetes Secret for the postgresql server TLS cert,
    # ignored if certificates.generate is true
    serverTLSSecret: ""
    # -- name of existing Kubernetes Secret for the postgresql server Certificate
    # Authority cert, ignored if certificates.generate is true
    serverCASecret: ""
  client:
    # -- enable using client certificates
    enabled: false
    # -- generate client certs using cert-manager. if true the following are
    # ignored: certificates.clientCASecret, certificates.replicationTLSSecret
    generate: false
    # -- name of existing Kubernetes Secret for the postgresql client Certificate
    # Authority cert, ignored if certificates.generate is true
    clientCASecret: ""
    # -- name of existing Kubernetes Secret for the postgresql replication TLS
    # cert ignored if certificates.generate is true
    replicationTLSSecret: ""

[jessebot]

tested locally with the ct install --target-branch main command it worked fine. not sure why it's breaking in ci 🤷